Photonic integrated circuit devices and methods of forming same
A photonic integrated circuit device includes a semiconductor substrate (e.g., wafer) having a chip region therein, which is bounded on at least one side thereof by a scribe line. The chip region includes an optical transmitter, an optical receiver and a test optical waveguide. This test optical waveguide is coupled to the optical transmitter and the optical receiver and overlaps the scribe line. During a substrate dicing operation, a portion of the test optical waveguide overlapping the scribe line is removed.
1. An integrated circuit device, comprising:
a substrate having a chip region therein bounded on at least one side thereof by a first scribe line, said chip region comprising an optical transmitter, an optical receiver and a test optical waveguide, which is coupled to the optical transmitter and the optical receiver and overlaps the first scribe line;
wherein the optical transmitter comprises a light-source device configured to generate an optical signal, and an optical modulator configured to: (i) divide the optical signal into first and second optical signal components, which are provided onto respective first and second optical waveguides, (ii) modulate a phase of the second optical signal component on the second optical waveguide relative to a phase of the first optical signal component on the first optical waveguide, and (iii) optically couple the modulated second optical signal component to the first optical signal component.
2. The device of claim 1 , wherein said substrate comprises a two-dimensional array of chip regions therein, which are separated from each other by a two-dimensional grid of scribe lines including the first scribe line.
3. The device of claim 2 , wherein the optical receiver comprises a photodetector optically coupled to the test optical waveguide.
4. The device of claim 3 , wherein the photodetector comprises a cladding layer on the substrate, a silicon core layer on the cladding layer and a germanium pattern on the silicon core layer; and wherein the test optical waveguide is connected to the silicon core layer.
5. The device of claim 4 , wherein the silicon core layer comprises an N-type doping region; and wherein the germanium pattern comprises a P-type doping region spaced from the silicon core layer.
6. The device of claim 4 , wherein the silicon core layer includes a first region, a second region and a third region extending between the first and second regions; wherein the germanium pattern extends on the third region; and wherein the test optical waveguide is optically coupled to the third region.
7. The device of claim 6 , wherein the first region comprises a P-type dopant and the second region comprises an N-type dopant.
8. The device of claim 6 , further comprising an input grating coupler, which is optically coupled to the silicon core layer.
9. The device of claim 1 , wherein test optical waveguide is configured to provide the optical receiver with an optical test signal that is output from the optical transmitter.
10. The device of claim 1 , wherein the test optical waveguide comprises an output segment connected to the optical transmitter, and an input segment connected to the optical receiver; and wherein the output segment crosses the first scribe line and the input segment crosses the first scribe line.
11. The device of claim 1 , wherein the optical transmitter comprises an optical output part that outputs the modulated optical signal.
12. The device of claim 11 , wherein the optical output part comprises:
a first output waveguide optically coupled to an output of the optical modulator to thereby receive a first modulated optical signal therefrom; and
a second output waveguide optically coupled to an output of the optical modulator to thereby receive a second modulated optical signal therefrom.
13. An integrated circuit device, comprising:
a substrate having a chip region therein bounded on at least one side thereof by a first scribe line, said chip region comprising an optical transmitter, an optical receiver, an output optical waveguide coupled to the optical transmitter, and a test optical waveguide, which is coupled to the optical transmitter and the optical receiver and overlaps the first scribe line;
wherein the optical transmitter is configured to output a first optical signal and a second optical signal, the first and second optical signals are complementary to each other, and the optical receiver comprises a photodetector coupled to the test optical waveguide.
14. The device of claim 13 , wherein the first optical signal is provided onto the output optical waveguide and the second optical signal is provided onto the test optical waveguide.